package java115.Thread;

public class Thread20 {
    public static void main(String[] args) throws InterruptedException {
    Thread[] threads = new Thread[20];
    for(int i=0; i<20; i++){
        final int n = i;
        threads[i] = new Thread(new Runnable() {
            @Override
            public void run() { 
                System.out.println(n);
            }
        });
    }
    for(Thread t : threads){
        t.start();
    }
    for(Thread t : threads){ 
        t.join();
    }
    System.out.println("OK");
}
}